dsh-travel-insurance: Travel Insurance Price Estimation

This plugin provides travel insurance price estimation for DSH development scenarios, using a pure Node.js local computation approach with no dependency on external APIs. The installation command is `dsh plugin add github:uckkk/dsh-travel-insurance`. To use it, call the `travel_insurance` tool to obtain a detailed result precisely calculated based on the parameters. The plugin runs with process-level permissions; it is recommended to review the source code and MIT license before installation.